Version 11.26 is good for now. There's no need to update if it's working well. New releases can be test driven at anytime - even if unlicensed - to check out features. Retain your old installer and registration. Any version can be had here, whether or not it's within your licensing six-month period.
There are several ways of editing (trimming) clips. One is to select a clip in the bin (top-left), then use the buttons under the preview window. Move the cursor to the desired start point, then click SET START. Move it to the end point and click SET END. Then use the ADD button to drop the trimmed clip to the timeline.
Note the chevron to the right of the ADD button that provides placement options. 
The same options are available via a right-click on the clip in the bin. Or a clip can simply be dragged to the sequence. Once on the sequence it can be trimmed and manipulated there. Editing on the sequence does not alter original clips in the bin.
The red and blue brackets can be hard to see, especially the blue one when it's far right. They will appear only when a bin clip is selected. When SET END is used, the blue bracket will show up prominently on the timeline.
In your case, the Sequence, under the SEQUENCES tab, had been inadvertently trimmed...
Normally, that item is not edited.
The preview window can be sized somewhat by dragging the white line just above the timeline up or down... 
Or preview can be undocked via the widget at the top-right.
Then it can be positioned, and sized by dragging its borders.
There were a number of flash frames - very short snippets - throughout the project. They are easily seen and deleted in Storyboard mode. and may have durations of .001, .203, etc. Very short. (These were not deleted for the revised VPJ.)
One way this may occur is when an edit is made near but not directly on a prior split point. To precisely position the cursor between two edits use the ||< and >|| buttons under the preview window to go to the junction. Then right clip on the new bin clip to be inserted and Place On Sequence at Cursor.
A final note: Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the chevron to the right of the Save Project button on the toolbar. Then you're protected, should mistakes occur. <ctrl-Z> (same as EDIT | UNDO) can also be used to backtrack, edit by edit.